1. Field of the Invention
This invention relates to compositions for improving lipid metabolism in animals including human beings, and more practically relates to compositions containing extract from medicinal plants, which are used in the form of medicine, drink or food. This invention relates, further, to methods for improving lipid metabolism, more practically lowering the level of triglyceride in the blood.
2. Prior Art
In recent years, there has been a steady increase in the number of heart patients suffering from ischemic ailments including angina pectoris and myocardial infarctions, which result from arteriosclerosis, especially coronary arteriosclerosis.
There are numerous factors which are thought to contribute to arteriosclerosis, hyperlipemia, high blood pressure, smoking, stress, diabetes, genetic factors, among others, but the highest risk factor is a high level (i.e. concentration) of lipids in the blood (i.e. hyperlipemia). Hyperlipemia is defined to be the condition in which the levels of both cholesterol and triglycerides (neutral fats) are higher than their normal levels, or the condition in which either of the levels is higher than the normal level; cholesterol and triglyceride are lipid components in blood serum.
When blood serum cholesterol or LDL cholesterol level (concentration) is high, the risk of arteriosclerosis also rises, and when the serum cholesterol level decreases, so does the incidence of coronary arteriosclerosis. It is known that among lipoproteins, LDLs are atherogenic, while HDLs are antiatherogenic. The risk of arteriosclerosis is frequently based solely on the level of HDL cholesterol in the blood, and therefore not enough attention is paid to the level of triglyceride in the blood which is also a clear indication of increased risk or developing arteriosclerosis (The New Medicine Outline, Vol. 36, Arteriosclerosis and Vascular Disorder, p. 20, published by NAKAYAMA Publishing Co. (1991)). In the case of familial hypercholesterolemia, high triglyceride levels increase the risk of both ischemic heart disease and cerebral angiopathy. In the case of critical region hypercholesterolemia, it is well known that the lowering of the level (concentration) of triglyceride is desirable. Therefore any therapy which results in lowering the level of neutral triglyceride in the blood (referred to as xe2x80x9cblood triglyceridexe2x80x9d hereinafter) is beneficial.
Focusing on this problem, the present inventors focused on a new approach to the prevention and treatment of hyperlipemia, i.e. lowering the risk of arteriosclerosis by lowering the level of blood triglycerides. It is important to note that this is different from, and complementary to, the conventional approach of controlling the level of cholesterol in the blood.
For the medicinal treatment of high blood lipid levels, new highly potent medicines have been developed and evaluated to be effective against familial hypercholesterolemia which had hitherto been refractory; these medicines act by a number of different mechanisms, e.g., absorption inhibition, biosynthesis inhibition and excretion promotion. There are also reports of positive effects resulting from the use of components of Chinese herbal medicines (bupleuri radix, ginseng radix, extractum glycyrrhizae, etc.) as well as various pharmacopoeial (i.e., officially recognized) medicines on lipid metabolism disorders such as hyperlipemia (Masahiro YAMAMOTO, Hyperlipemia, Metabolism 26 (Extra publication: Chinese Medicines): 212-219, 1992).
However, the above-mentioned reference does not mention any of the following: ICHO (ginkgo: Ginkgo biloba) leaves, GAJUTSU (zedoariae rhizoma) the KYOUOU (curcumae rhizoma), nor does it mention lowering the level of blood triglycerides as an approach for therapy.
Generally, it is understood that herbal medicines act on a variety sites and by a variety of mechanisms and metabolisms and that these various actions function collectively to result in effective treatments. Accordingly when new components or Chinese herbal medicines are discovered to be effective against hyperlipemia, these newly discovered components can be expected to be useful and effective when administered alone as well as when administered in combination with herbal medicines or officially recognized medicines.
In consideration of the above, the present inventors intended to find, by screening Chinese herbal medicines, substances capable of improving lipid metabolism and thus lowering the level of blood triglyceride, which could then be used alone or in combination with Chinese herbal medicines or officially recognized medicines.
Further, the present inventors intended to provide the above-mentioned compositions in the form of medicine, drink or food.